How to process incoming email with a regex and forward it further?

Question

PHP

You need to pass the incoming email through the regular expression (throwing out the excess) and forward the letter further.
Previously, I used for this purpose "Mail autoresponder / Process with script" in the server panel of ISPManager Lite 4.x + my own php script, into which the incoming letter was transferred. But from the version of the panel 5.x, the "Process with a script" function was thrown out.
Recommend a suitable solution. Perhaps a budget hosting with similar functionality, an email-pipe with the ability to pass through a regex (if it exists), or something else. I would like to avoid the "obvious" solution with crutches in the form of a cron every minute to check / extract mail.
Thanks for the help!